Platinum Medallions beware! Ticket was booked for me, agent chose Basic Economy Fare to save $50. Delta wants more than $600 to change. No seat selection, upgrades, or same day confirmed changes.

Not even allowed to fly standby, meaning delta will fly empty seats rather than serve their loyal customers.

Delta "can't" make exceptions even for their most loyal flyers. Ouch!

Too make the rules fare across the board, the agent clicked on the "I agree to the terms and conditions". Next time book a ticket with a bit of flexibility. these are the term your agent agreed with and is stated on the Delta website:

With Some Key Differences
In Basic Economy you’ll experience:

Complimentary carry-on bag. Overhead bin space may be limited, so your carry-on bag may be gate checked free of charge
Checked bag fee applies depending on the route. Please visit our Baggage and Travel Fees page for details
Seat assignment is free after check-in
Ticket changes or upgrades are not allowed*
* Ticket changes or refunds not allowed after the Risk-Free Cancellation period. Basic Economy travelers are not eligible for paid or complimentary access or upgrades to premium seats, including to Delta Comfort+® or Preferred Seats; and no paid access to Priority Boarding.